.
During
the past years, Feringa and co-workers have developed very efficient
palladium-catalyzed methodologies for the cross-coupling of
organolithium reagents.
They have now described that nickel-based
catalytic systems are also able to successfully cross-couple these
organometallic reagents to a variety of (hetero)aryl electrophiles ( Chem. Eur. J. 2016, 22, 3991).
The reactions take place in toluene at room temperature with a 50%
molar excess of the organolithium reagent and are usually finished
within an hour.
In order to limit the formation of reduced (hetero)aryl
electrophile, a different catalyst has to be used for the efficient
coupling of aryl- or alkyl-lithium reagents, a N-heterocyclic
carbene ligated one (C3 above) for the former and
bis(diethyldiphosphino)ethane ligated one (C1 above) for the latter.
While the substrate scope appears to be limited by the high reactivity
of the organometallic partner, these nickel-catalyzed protocols allow a
number of less usual electrophiles, such as methyl ethers or fluorides,
to engage in the cross-coupling reaction.
See original article
Homogeous Catalysis
Nickel-Catalyzed Cross-Coupling of Organolithium Reagents with (Hetero)Aryl Electrophiles (pages 3991–3995)Dorus Heijnen, Dr. Jean-Baptiste Gualtierotti, Dr. Valentín Hornillos and Prof. Dr. Ben L. Feringa
Version of Record online: 4 FEB 2016 | DOI: 10.1002/chem.201505106
Version of Record online: 4 FEB 2016 | DOI: 10.1002/chem.201505106
Nickel-catalyzed cross-coupling of aromatic electrophiles with organolithium reagents is presented. The use of a commercially available nickel N-heterocyclic
carbene complex allows reaction with a variety of (hetero)aryllithium
compounds, whereas a commercially available electron-rich nickel
bisphosphine complex smoothly converts alkyllithium species into the
corresponding coupled product.
///////////
